In high power laser system, laser-induced damage threshold (LIDT) in optical coating is very important for obtaining high performances. The dependence of LIDT on the pulse duration and the repetition rate are well known phenomena. But recently, LIDT was found to have strong temperature dependences in the bulk, surface of substrates, and in coatings. This temperature dependence of LIDT was carefully measured, and the damage formation model was constructed regarding to this temperature dependence. This paper introduces LFEX laser system for First Ignition scheme in the laser fusion. A large-scale pulse compression chamber was designed and constructed, and segmented grating system has been employed for large-scale pulse compressor. This compressor provided good pulse compression performances, but we observed a heavy oil-contamination of optics in this chamber. We have analyzed contaminants and evaluated the effects of the contamination. We also developed new cleaning methods to remove contamination from the coating, and the quantitative analysis of contamination on LIDT was made. We have investigated the characteristics of LIDT in dielectric coatings under the controlled contamination. LIDT of coating drops to 1/2 in the saturated toluene vapor at room temperature.

Date Published: 19 July 2013
PDF: 6 pages
Proc. SPIE 8786, Pacific Rim Laser Damage 2013: Optical Materials for High Power Lasers, 87860B (19 July 2013); doi: 10.1117/12.2021026

Published in SPIE Proceedings Vol. 8786:
Pacific Rim Laser Damage 2013: Optical Materials for High Power Lasers
Jianda Shao; Takahisa Jitsuno; Wolfgang Rudolph, Editor(s)